thompson



(.No Model.) 2 Sheets-Sheet 1'. E. P. THOMPSON.

INGANDESGENT ELECTRIC LAMP.

Patented Oct. 4

LiklNlTii Iii l v v I- INVE N T U H a flit-always 5 2 Sheets-Sheet 2.

Patent-ed 001;. 4, 1887.

IN \IE N TU H i 6? W By 7 A Jfilorlzegag 11?. THOMPSON.

INOANDESOENT ELEOTRIC LAMP.

(No Model.)

Fz'c

filE

ATTEST the filament in the usual manner.

men t.

' UNIT -n STATES PATENT OFFICE.

RD PMIHOMPSON, OF ELlZABETH, NEIV JERSEY.

INCANDESCENT ELECTRIC LAMP.

SPECIFICATION forming part of Letters Patent No. 371,003, dated October 4, 1887.

Application filed February 28, 1887. Serial No. 229,094.

To all whom, it may concern.-

Be it known that I, EDWARD P. THOMPSON,

IQ of connecting them in circuit, the object being to provide a lamp capable of being turned down or ofgiving but a small amount of light whenever itis desired to reduce the illumination.

: The invention consists, in general terms, in

constructing a small section of the filament of an incandescent electric lamp in such manner that it may be included in a separate circuit, or included in different secondary electric 2o circuits derived from electric converters independently of the remaining portion of the filament at will. This small section may then be employed,to the exclusion ofthe remaining portion of the filament,whenever but asmall 25 illumination is desired.

In the accompanying drawings, Figure 1 illustrates an incandescent electric lamp, together with a system of circuits,embodying the features of the invention, and Fig. 2 illuso t-rates the application of the invention to a chandelier. Fig. 3 illustrates a modification.

Referring to the figures, A represents an incandescent-electric-lamp globe, and Bits filament. The leading-in wires a and a support A third wire, a leads to a point, a, a short distance above the point at which the leading-in wire a terminates. Thus there is included between the wires (6 and a a short section, I), ofthe fila- It is designed that this section shall be included in the circuit when but a dim light is required.

The invention is illustrated as applied to a system of electric distribution in which electric converters or secondary generators are employed for delivering the currents to the lights. In this instance E represents a suitable source of intermittent or alternating electric currents,which are conveyed by conduct- 5o ors L L to the'primary coil P of a converter, 0.

The secondary coil S has its respective termi- 'leads to the leading-in wire a (No model.)

nals connected with conductors Land L, from which the conductors H are derived. These latter conductors lead, respectively. to the terminals of the leading-in wires of a In this manner alternating currents are delivered to the lamp as required.

WVhen it is desired to reduce the light, a switch, 8, included in the conductor Z, may be opened, thus interrupiug the connections to the leading-in wire a. The conductor Pleads from this leading-in wire to one terminal of the secondary coil 8 of a converter, 0. Aconductor, 1*, leads from the other terminal of this coil to the leading-in wire a The primary coilp of the converter 0 is included in a circuit, Z Z, derived from the conductors Zand A switch, 8, included in the conductor Z when closed, completes the connections th rough the primary coil of the converter 0. This converter may, if necessary, reduce thepotential of the current, so that the current delivered through the conductors Z 6* shall be much less than that delivered to the primary coil 1) and adapted to render incandescent the small section b of the filament B. This section may,if desired, be of a different specific conductivity from the remaining portion of-the filament. It will thus be seen that by opening the switch 8 and closing the switch 8' the main portion of the filament may be cut out of circnit and the section b included in the circuit of the secondary coil of the converter 0. This organization will be found convenient for night-lamps and similar purposes.

Referring to Fig. 2, the invention-is illus trated as applied to a chandelier. In this instance the conductors L L lead through the support of the chandelier to the leading-in wires a a, as before. The switch .9 serves to make and break the connections to the terminal a. The leading-in wire-a is connected by the conductor i with a switch, 8, which serves to make and break the connections of the circuit when turned by means ofthe handle t, in any convenientmanner,and the conductor l leading from this switch, passes to one terminal of the secondary coils of the converter 0. The other terminal of this coil is connected through conductor Z to the conductor Lwhich In this manner the section b of the filament may beintoo cluded in the circuit,to the exclusion of the re maining portion of the filament B, at will. Other conductors, L L and Z Z, lead to other lights in the chandelier.

The converter may with advantage be located in some portion of the chandelier, or in the support of the same, as indicated.

In Fig. 3 the invention is illustrated as applied to a subsidiary lamp, A, the filament b of which takes the place of the section bin the former instance. The switch 8 serves to interrupt the connections through the filament B of the lamp Aand to complete the connections through the filament I), in the manner already described. The system of circuits is the same as that set forth.

I claim as my invention- 1. The combination, with a converter and its primary and secondary circuits, of a subsidiary converter having its primary circuit derived from said secondary circuit, an incandescent electric lamp, an independent conductor leading from a point in the length of the filament,and a circuit for thesecondary coil of the subsidiary converter with which said independent leading-in wire and one terminal of the filament are respectively connected.

2. The combination of two electric converters, means for supplying currents to the primary coils of the same, an electric lamp having an incandescent filament, a conductorleading from a point in the length of the filament, thus dividing off a section of the filament,and circuit connections whereby said section may be placed in circuit with one of the converters, or a greaterportion of the filament placed in the circuit with the other converter.

3. In a system of electric lighting, a main converter delivering currents of a given potential, a subsidiary converter supplied from the secondary circuit thereof, an incandescent electric lamp, circuit connections whereby said lamp may be normally included in the secondary circuit of the first-named converter, a short section of a filament, and circuit-counections whereby the latter may be placed in the circuit of the secondary coil of the second converter.

4. The combination, with two or more incandescent electric lamps, of a closed circuit including them in series,- an electric converter in a normally open circuit, and means for completing thelast-named circuit through one of the lamps.

5. The combination of two incandescent electric lamps of difierent resistances, connected in series, an electric converter in circuit with one of the lamps, and a common circuitcontroller for both lamps, substantially as described.

In testimony whereof I have hereunto subscribed my name this 18th day of February, A. D. 1887.

EDNVARD P. THOMPSON.

Witnesses:

DANL. W. EDcEooMB, CHARLES A. TERRY. 

